mystery girl AMY WINEHOUSE'S jailbird hubby is dating?

The redhead BLAKE FIELDER-CIVIL affectionately calls "Darling Tickle" is 25-year-old SARAH THOMAS.

Blake is smitten with the office receptionist, who has secretly been visiting him in Pentonville Prison, while unreliable Amy has repeatedly been a no-show.

She is also helping him get clean of drugs while he's inside.

Blake is now planning a future with Sarah, telling her: "Just say the word and I'll dump Amy. I love you more than I could ever love my wife. You're all that matters to me."

And, pouring out his heart to his mum GEORGETTE, he said: "Unlike Amy, Sarah always turns up to visit me. She's always there for me.

"She knew me before I got addicted to drugs and told me how much she hated the way I changed when I got stoned with Amy. She's helped me get clean of drugs in prison. Now I feel I'm in control and I appreciate what an absolute s*** I've been when I was stoned.

"I'm determined to stay clean."